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Performance Analysisof a Bi-Objective Model for Routing and Wavelength Assignmentin WDM Networks, Journal of Telecommunications and Information Technology, 2010, nr 3
Get PDFEstablishing end-to-end connections on wavelength division multiplexing (WDM) networks requires setting up lightpaths, defining the sequence of optical fibres and the wavelength in each fibre (the routing and wavelength assignment problem) for traffic flow. This paper reviews a bicriteria model for obtaining a topological path (unidirectional or symmetric bidirectional) for each lightpath request in a WDM network, developed by the authors, and presents a performance analysis of the model by considering important network performance measures. An extensive performance analysis of the two bicriteria model is presented, comparing the performance metrics obtained with the monocriterion models using the same objective functions, in five different reference networks commonly used in literature
Planning System for Multi-Agent Based Reconfigurable Fixtures, Journal of Telecommunications and Information Technology, 2010, nr 3
Get PDFThis paper describes a concept of the planning system for self adaptable, reconfigurable fixtures composed of mobile locators (robotic agents) that can freely move on a bench and reposition below the supported part, without removing the part from the fixture. The main role of the planner is to generate the admissible plan of relocation of the mobile agents. A constrained nonlinear optimization problem is formulated to find the optimal locations for supporting heads
Novel Method of Improving Electrical Properties of Thin PECVD Oxide Films by Fluorination of Silicon Surface Region by RIE in RF CF4 Plasma, Journal of Telecommunications and Information Technology, 2010, nr 1
Get PDFThis study describes a novel technique to form good quality low temperature oxide (< 350◦C). Low temperature oxide was formed by N2O + SiH4:N2 plasma in a plasma enhanced chemical vapour deposition (PECVD) system on the silicon surface reactively etched in CF4 plasma (RIE – reactive ion etching). The fabricated oxide demonstrated excellent (for low temperature dielectric formation process) currentvoltage (I−V) characteristics, such as: low leakage current, high breakdown voltage and good reliability. Experimental results indicate that the proposed method of fluorine incorporation into the SiO2/Si inteface improves electrical parameters of MOS structures
Rule Based Speech Signal Segmentation, Journal of Telecommunications and Information Technology, 2010, nr 4
Get PDFThis paper presents the automated speech signal segmentation problem. Segmentation algorithms based on energetic threshold showed good results only in noise-free environments. With higher noise level automatic threshold calculation becomes complicated task. Rule based postprocessing of segments can give more stable results. Off-line, on-line andextrema types of rules are reviewed. An extrema-type segmentation algorithm is proposed. This algorithm is enhanced by a rule base to extract higher energy level segments from noise.This algorithm can work well with energy like features. The experiments were made to compare threshold and rule-based segmentation in different noise types. Also was tested if multifeature segmentation can improve segmentation results. The extrema rule-based segmentation showed smaller error ratio in different noise types and levels. Proposed algorithm does not require high calculation resources. Such algorithm can be processed by devices with limited computing power
The Template Selection in Biometric Systems Based on Binary Iris Codes, Journal of Telecommunications and Information Technology, 2010, nr 4
Get PDFSince the variability of data within readings from the same person is intrinsic property of every biometric system, the problem of finding a good representative – the template – was recognized and present since the beginning of biometrics. This problem was solved differently for different biometric types, yet usually the template somehow averages the collected data samples. However, for the iris type, the template is usually just one or a few samples. In this paper we describe the experiments that suggest that the averaging is also justified in case of iris template creation. This is an important fact, which can significantly improve a performance of biometric template protection methods for iris
Telecommunications, UniversalService and Poverty in Mexico: a PublicPolicy Assessment (1990–2008), Journal of Telecommunications and Information Technology, 2010, nr 2
Get PDFThis article analyzes the design and implementation of telecommunications service policies targeted at the poorest regions of Mexico (1990–2008). It begins by defining universal access and service policies, their economic and social rationale. Secondly, it discusses the scope of public policies on universal service provision designed by Mexican authorities to achieve the goal of universal access. Thirdly, the paper analyzes the distributive effects of this set of policies among the poorest sectors of the population. The sources on which this research was based were two national surveys: the House-hold Income and Expenditure Survey (2008), and the House-hold Survey of the Access and Use of Information Technologies (2007). The additional information on regional economic development was based on the poverty indexes by the national population council and economic information given by Mexico’s Census Bureau. Additional use was made of the annual reports prepared by Ministry of Communications, statistics published by the Federal Telecommunications Commission and official documents prepared by the government agencies. Finally, a series of in-depth interviews was conducted with the former representatives of the Office of Rural Telephony. Finally, the article discusses, in the light of available evidence, possible explanations for the apparent failure of the universal service policy that was implemented to bring at least basic voice services to Mexico’s neediest
The Effect of High Temperature Annealing on Fluorine Distribution Profile and Electro-Physical Properties of Thin Gate Oxide Fluorinated by Silicon Dioxide RIE in CF4 Plasma, Journal of Telecommunications and Information Technology, 2010, nr 1
Get PDFThis study describes the effects of high temperature annealing performed on structures fluorinated during initial silicon dioxide reactive ion etching (RIE) process in CF4 plasma prior to the plasma enhanced chemical vapour deposition (PECVD) of the final oxide. The obtained results show that fluorine incorporated at the PECVD oxide/Si interface during RIE is very stable even at high temperatures. Application of fluorination and high temperature annealing during oxide layer fabrication significantly improved the properties of the interface (DitmDitmb decreased), as well as those of the bulk of the oxide layer (Qef f decreased). The integrity of the oxide (higher Vbd ) and its uniformity (Vbd distribution) are also improved
Optimization of the Multi-Threaded Interval Algorithm for the Pareto-Set Computation, Journal of Telecommunications and Information Technology, 2010, nr 1
Get PDFPrevious investigations of the authors surveyed the possibility of applying interval methods to seek the Pareto-front of a multicriterial nonlinear problem. An efficient algorithm has been proposed and its implementation in a multicore environment has been done and tested. This paper has two goals. First one is to tune the developed algorithm to increase the speedup of the multi-threaded variant. The second one is to extend the algorithm to compute not only the Pareto-front (in the criteria space), but also the Pareto-set (in the decision space). Numerical results for suitable test problems are presented
Wybrane aspekty zjawiska cyberterroryzmu. Telekomunikacja i Techniki Informacyjne, 2010, nr 1-2
Get PDFArtykuł został poświęcony wybranym aspektom zjawiska cyberterroryzmu, które towarzyszy współczesnemu rozwojowi techniki, opartemu w znacznej mierze na teleinformatycznych narzędziach wymiany informacji i towarów. Wyjaśniono pojęcie cyberprzestrzeni oraz omówiono istotę cyberterroryzmu jako formy cyberprzestępczości o charakterze terrorystycznym. Przedstawiono ponadto zidentyfikowane obecnie formy działalności przestępczej i terrorystycznej w cyberprzestrzeni, a także wybrane regulacje polskiego systemu prawnego służące jej zwalczaniu